Piston pump



FIG. 1 is a front view of the piston pump of my design;

FIG. 2 is a rear view of the piston pump of FIG. 1;

FIG. 3 is a bottom view of the piston pump of FIG. 1;

FIG. 4 is a top plan view of the piston pump of FIG. 1;

FIG. 5 is a left elevation of the piston pump of FIG. 1;

FIG. 6 is a right elevation of the piston pump of FIG. 1; and,

FIG. 7 is a perspective view of the piston pump of FIG. 1.

The broken lines in FIGS. 1, 2, 3, 6 and 7 are included for the purposeof illustrating portions of the piston pump that form no part of theclaimed design.

CLAIM The ornamental design for piston pump, as shown and described.